For some time now (cannot remember since when), one of the three admins of my site has not been able to edit author names of posts in draft. I and the third admin can. I triple-checked the user account for the admin in question, and the settings on her profile look exactly like those of mine and the other admin.
The only difference is that she was added as an admin about a year or so after me and the other admin. We’ve been admins since the blog was born in 2008.